1. OSC
    An implementation of the OpenSoundControl protocol
  2. Osicat
    Operating system interface library mainly for Unix
  3. Other CLikis
    If you're running a web site based on CLiki, feel free to add a link to it here
  4. outer-parentheses-free-repl
    outer-parentheses-free-repl (OPFR) lets you input the outermost s-exp into your REPL without having to surround it with parentheses
  5. Overlord
    Overlord is an experimental build system for Common Lisp, inspired by Redo
  6. OWL
    The W3C OWL 2 Web Ontology Language (OWL) is a Semantic Web language designed to represent rich and complex knowledge about things, groups of things, and relations between things.
  7. package-renaming
    package-renaming is a library for locally renaming CL packages
  8. packer
    The PACKER binary format library implements a "little language" for C-style structures, along the lines of Perl's pack() or Python's struct module
  9. PAIP
    Paradigms of Artificial Intelligence Programming: Case Studies in Common Lisp
  10. pal
    PAL is a Common Lisp multimedia library that provides simple and easy to use Lisp interface for all your basic graphics and audio needs